Suchergebnisse

Spring oilseed rape is an important oilseed crop, the area of which has increased significantly in northern Europe, including Estonia. Spring oilseed rape is predominantly autogamous but cross-pollination can have several positive effects, including higher seed yield and better quality. Hence, it is profitable to encourage high number of bees as the main pollinators in oilseed rape fields. On the other hand the expansion of oilseed rape growing area in Europe has increased the number of pests. This has resulted in the need to use more pesticides which have negative effects also on useful organisms, including pollinators. The aims of the current thesis were from one side to study the impact of oilseed rape (as crop which has high nutrient demand) foliar fertilization with different microfertilizers on the number of flower visiting bees (honey bees, bumble bees and solitary bees) and on the other hand the repellency of insecticide Fastac 50 EC on honey bees and the effect of sub-lethal doses of insecticide on respiratory pattern of bumble bees as it is a good indicator of their physiological state. The results of the study showed that to secure a higher number of pollinators for achieving higher seed yield and other benefits deriving from cross-pollination spring oilseed rape should receive proper complex fertilization. Applied microfertilizers turned out to be useless in terms of increasing the number of pollinators. In addition, the study tended to confirm that Fastac 50 EC does not show repellency for honey bees in field conditions. Flower density seemed to be the main signal for bees and might override the repellent effect. Even solutions with ten times lower concentrations of Fastac 50 EC than registered field rate in Estonia affected significantly the respiratory patterns of bumble bees and decreased the longevity. The study shows that as in field conditions additional factors may affect the choices of bees, laboratory and semi-field studies often do not reflect the situation in field conditions. The sub-lethal doses of pesticides bees encounter do affect the physiological state of the pollinators, being thus one possible reason for global pollination crisis. At the same time the application of pesticides is quite new phenomenon from the evolutionary perspective and pollinators have not learned to recognize the hazards. Pesticides should not be used routinely and prophylactically without regard to pest incidence but the need for the application should be previously monitored. The protection of pollinators against negative effects of pesticides should also be supported by the policies (e.g. through the environmental measures of the European Union common agricultural policy). In addition, further research on the ecotoxicity of pesticides is needed and more environmentally friendly growing technologies should be worked out (e.g. entomovector-technology and biopesticides). ; Suviraps on oluline õlikultuur, mille kasvupind on Põhja-Euroopas, k.a Eestis, oluliselt suurenenud. Raps on peamiselt isetolmlev, kuid risttolmlemisel on mitmeid eeliseid, sh tõstab seemente kvaliteeti ja kvantiteeti. Seetõttu on mesilaselaadseid kui rapsi peamisi tolmeldajaid igati kasulik soodustada. Teisest küljest on rapsi kasvupinna suurenemine toonud kaasa ka kahjurite arvukuse tõusu, mistõttu on vaja kasutada rohkem pestitsiide. Viimased avaldavad aga negatiivset mõju ka kasulikele organismidele, sh tolmeldajatele. Käesoleva doktoritöö eesmärgiks oli ühelt poolt uurida rapsi kui suure toitainetevajadusega kultuuri lehekaudse mikroväetistega väetamise mõju õisi külastavate mesilaselaadsete (meemesilaste, kimalaste ja erakmesilaste) arvukusele ning teiselt poolt repellentse insektitsiidi Fastac 50 EC eemalepeletavat toimet meemesilastele ja sub-letaalsete dooside mõju kimalaste hingamisrütmidele, mis on heaks füsioloogilise seisundi näitajaks. Uurimus näitas, et tolmeldajate arvukuse soodustamiseks on rapsi vaja kõrgema saagi ja teiste risttolmlemisest tulenevate eeliste tagamiseks kompleksväetisega väetada. Katses kasutatud lehekaudsed mikroväetised aga tolmeldajate arvukust enam täiendavalt ei suurendanud. Lisaks leiti, et põllu tingimustes ei avaldunud Fastac 50 EC väidetavalt repellentne toime meemesilastele – kõige olulisemaks signaaliks osutus õite tihedus, mis võis üle kaaluda insektitsiidi väidetavalt eemalepeletava toime. Katse põhjal selgus, et isegi kümme korda madalama kontsentratsiooniga Fastac 50 EC lahus kui on Eestis tegelik registreeritud põllul kasutatav doos, mõjutas oluliselt kimalaste hingamisrütme ja vähendas nende eluiga. Antud uurimustöö tulemused näitavad, et labori- ja väikeseskaalaliste põldkatsete tulemused ei peegelda tihti tegelikku olukorda põllu tingimustes. Sub-letaalsed pestitsiidi doosid mõjutavad tolmeldajate füsiloogilist seisundit ning võivad seega olla üheks globaalse tolmeldamiskriisi põhjuseks. Seejuures on pestitsiidide kasutamine evolutsioonilisest vaatepunktist küllaltki uus nähtus ja tolmeldajad ei ole veel õppinud riske ära tundma. Pestitsiide ei tohiks kasutada rutiinselt ja lihtsalt profülaktika mõttes, vaid vajadust selle järele tuleks põllul eelnevalt seirata. Tolmeldajate kaitsmist pestitsiidide negatiivsete mõjude eest tuleks toetada ka läbi erinevate poliitikate (sh läbi Euroopa Liidu ühise põllumajanduspoliitika keskkonnameetmete). Vajalikud on täiendavad uurimused pestitsiidide toksilisusest elusorganismidele ning välja tuleks töötada keskkonnasõbralikumaid kasvatustehnoloogiaid (nt entomovektor-tehnoloogia ja biopestitsiidid). ; Publication of this thesis is supported by the Estonian University of Life Sciences and by the Doctoral School of Earth Sciences and Ecology created under the auspices of European Social Fund.

A large proportion of European biodiversity today depends on habitat provided by low-intensity farming practices, yet this resource is declining as European agriculture intensifies. Within the European Union, particularly the central and eastern new member states have retained relatively large areas of species-rich farmland, but despite increased investment in nature conservation here in recent years, farmland biodiversity trends appear to be worsening. Although the high biodiversity value of Central and Eastern European farmland has long been reported, the amount of research in the international literature focused on farmland biodiversity in this region remains comparatively tiny, and measures within the EU Common Agricultural Policy are relatively poorly adapted to support it. In this opinion study, we argue that, 10 years after the accession of the first eastern EU new member states, the continued under-representation of the low-intensity farmland in Central and Eastern Europe in the international literature and EU policy is impeding the development of sound, evidence-based conservation interventions. The biodiversity benefits for Europe of existing low-intensity farmland, particularly in the central and eastern states, should be harnessed before they are lost. Instead of waiting for species-rich farmland to further decline, targeted research and monitoring to create locally appropriate conservation strategies for these habitats is needed now.

A large proportion of European biodiversity today depends on habitat provided by low-intensity farming practices, yet this resource is declining as European agriculture intensifies. Within the European Union, particularly the central and eastern new member states have retained relatively large areas of species-rich farmland, but despite increased investment in nature conservation here in recent years, farmland biodiversity trends appear to be worsening. Although the high biodiversity value of Central and Eastern European farmland has long been reported, the amount of research in the international literature focused on farmland biodiversity in this region remains comparatively tiny, and measures within the EU Common Agricultural Policy are relatively poorly adapted to support it. In this opinion study, we argue that, 10years after the accession of the first eastern EU new member states, the continued under-representation of the low-intensity farmland in Central and Eastern Europe in the international literature and EU policy is impeding the development of sound, evidence-based conservation interventions. The biodiversity benefits for Europe of existing low-intensity farmland, particularly in the central and eastern states, should be harnessed before they are lost. Instead of waiting for species-rich farmland to further decline, targeted research and monitoring to create locally appropriate conservation strategies for these habitats is needed now. ; Peer reviewed

A large proportion of European biodiversity today depends on habitat provided by low-intensity farming practices, yet this resource is declining as European agriculture intensifies. Within the European Union, particularly the central and eastern new member states have retained relatively large areas of species-rich farmland, but despite increased investment in nature conservation here in recent years, farmland biodiversity trends appear to be worsening. Although the high biodiversity value of Central and Eastern European farmland has long been reported, the amount of research in the international literature focused on farmland biodiversity in this region remains comparatively tiny, and measures within the EU Common Agricultural Policy are relatively poorly adapted to support it. In this opinion study, we argue that, 10 years after the accession of the first eastern EU new member states, the continued under-representation of the low-intensity farmland in Central and Eastern Europe in the international literature and EU policy is impeding the development of sound, evidence-based conservation interventions. The biodiversity benefits for Europe of existing low-intensity farmland, particularly in the central and eastern states, should be harnessed before they are lost. Instead of waiting for species-rich farmland to further decline, targeted research and monitoring to create locally appropriate conservation strategies for these habitats is needed now. ; peerReviewed